Internal-combustion engine



April 27, 1926. 1,582,763

T. LAFITTE INTERNAL comsus'rxon ENGINE Filed July 2 1922 2 Sheets-Sheet 1 VIII/Ill 7767/6 VIII/Ill VI/1.11 I! 27 1926. Apnl T. LAFlTTE INTERNAL COMBUSTION ENGINE Filed July 1922 2 Sheets-Sheet 2 J22 $622 22 Uea/arafgyQZ/a Patented Apr. 27, 1926.

UNITED STATES PATENT OFFICE.

mmononn LAIITTE, or rams, Eamon.

INTERNAL-COMBUSTION ENGINE.

Application filed July 27, 1922. Serial No. 577,921.

. four-cycle type and is chiefly applicable to engines for aviation and like purposes wherein the atmospheric pressure is variable and is generally below the pressure at the ground.

The engine according to my invention has disposed within the crankcase various partitions dividing the same into separate chambers, so that each of said chambers can be connected with two cylinders whereof the pistons move in concordance .but the inlet valves are alternately opened.

The invention relates more particularly to means for controlling the communication of saidchambers with each other and also with the atmosphere, for the purpose ofvarying the amountof carburated air supplied to the cylinders as required. This control may be effected by hand or automatically .by means of the vacuum in the suction conduit of the engine whereby the cylinders shall be filled at a substantially. constant pressure even i where the atmospheric pressure is quite variable as in the case of aviation.

The invention also comprises an engine having a plurality of cylinders disposed in V-shape in pairs and a crank whose axis of rotation is perpendicular to the planes of the various cylinders but is excentric to the ver-' tex thereof.

The invention further com rises a crank case divided by partitions lnto chambers each of which communicates with one of the pairs of cylinders and with the exterior.

The accompanying drawing is given for demonstrative purposes and indicates the disposition which is adopted as well as the operation in the caseof a 16-cylinder aviation engine of the V-type.

Fig. 1 is a lengthwise section on the lines A-A, B-B and CC of Fig. 2, and,

'Fig. 2 is a cross-section on the line DD of Fig. 1, with the relief valve closed.

Fig. 3 is a cross-section on the line DD andan end view of the relief valve in the open position.

Fig. 4 a lengthwise section of the inlet valve gear on the line EE of Fig. 2, and

F1g. 5 1s a lengthwise section of the relie valve 1n the open position on the line A-A of Fig. 2.

Fig. 6 is a vertical section of a modified form of construction of the inlet devices for one of the cylinders.

The cyhnders 1, 2, 3, 414, 15, 16, whereof only a certaln number are shown in the drawing, are disposed in two groups of 8 cyllnders dlsposed in V-shape in pairs, with the axes forming an the maximum acute angle. This result is obtained by an axial displacement of cylinders -1, 2, 3,-7, 8, Fig. 2. The cylinders contain. pistons 17, 18, 19 mounted with connecting rods 20, 21,-26 and a crankshaft 27 whose axis of rotation 1s perpendicular to the planes of the various cylinders but is excentrlc with respect to the vertex thereof. The latter turns in a casing 28 whose artitions 31, 32, 33, 34, 35 form tlght chambers, each of which communicates w th one of the pairs of cylinders and also with the exterior at the proper time by. a

revoluble valve 38 rotating at engine speed,-

or by like means such as automatic or con- }rlplled poppet valves, slide valves or the The valve 38 provides for the inlet of air -at;the ends thereof andsupplies the same to sald chambers through ports 39, 40 and conduits 41, 42. A relieving drum or valve 43 actuated by armsAA: connects any two consecutive chambers together as well as to the exterior through the passages 45, 46, ports 47 and conduits48. Each of the chambers 3235 is connected at the top with a second revoluble valve 62 rotating at engine speed and whereof each end communicates wlth a carburetter or 61 whose outlets are connected with the inlets 49, 50 supplying the inlet valves 51, 52 controlledas for the exhaust valves, not shown-by the rockers 53,

54 controlled by a cam shaft 55 operating at half the engine speed and slidable upon the shaft. The inlet earns 56, 57 have a transverse outline which gradually varies from one end of the cam -to the other and in such 'manner that the end outlines will provide for valve lift of the normal duration, or some 200 of the rotation of the crankshaft, for

one of the end outlines and 25 per cent longer for the other. Lengthwise motion of the cam shaft is afiorded by a hand lever 58 whose ends engage a circular groove 59 in said shaft.

The operation of said apparatus is as follows: The engine is supposed to rotate in the sense of the arrows, Figs. 2 and 3. The crankshaft is shown in Figf 1 with the cranks in vertical and horizontal planes; in Fig. 2 at the time of compression in chamber 31, and in Fig. 3 duringthe suction in said chamber. If the relief valve 43 is in the first place supposed to be closed, Fig. 2, the reciprocatin motion of pistons 17, 19 will vary the volume of chamber 31, and as the angle between the two cylinder groups is very small, the dead centers of pistons 17, 19 will be very near each other, and will be closer according as the angle is more acute. The volume of chamber 31 is thus a maximum. at the moment comprised between the upper dead centers of pistons 1'? and 19 and a minimum at the moment comprised between the. lower dead centers. The variation in volume of the chamber is about twice the volume due to the piston, or two cylinder-fulls. After clearing the lower dead center, the port 39 of the suctionvalve 38 opens the conduit 42 and the outer air now fills up the chamber 31. At the upper dead center the valve 38 closes the conduit 42, and the second valve 62 now connects the chamber 31 with the carburettor devices 60, 61 and the'inlet piping 49, 50. a

The inlet VQlXG of one of the two cylinders connected with chamber 31 will now open under control of cam shaft 55, and the two cylinder-frills of air which come from the chamber 31 and are suitably carburated will be discharged Should the air drawn in from the atmosphere have had a pressure of 1 kilogram per square centimeter, the discharged air filling the cylinder will have double the pressure, or 2 kilograms.

The said improvements are not especially intended to double the filling pressure, but

chiefly to maintain this engine filling pressure at a constant value and substantially at 1 kilogram per square centimeter, whereby the engine shall be enabled to maintain the full power at all altitudes, that IS, at all pressures of the air at the inlet. For this purpose, when the engine is running at the ground level, the relied valve 43 is entirely opened by levers 44; two consecutive chambers for instance 31 and .32 are connected togetherand to the atmosphere by passages 45, 46, 47, 48, and as the respective cranks of the crankshaft moving in said chambers are displaced by 180, the maximum volume of one chamber will -coincidesubstantially with. the minimum of the second chamber. The air in said chambers will therefore be at this moment exactly at the atmospheric pressure, and the cylinders drawing in air through the suction valves which are sucinto said cylindcr.

cessively opened will be filled up at atmospheric pressure, and the cylinders drawing in air through the suction valves which are successively opened will be filled up at atmosphericpressure if these latter are closed with a normal retardation, or some 20 to 30 of crankshaft motion. But when upon the ground, the cam shaft 55 has been operated by handle 58 so that the cams 56, 57 controlling the rockers by reason of their outline will give the maximum opening, or some 25 per cent above the normal; the pistons then discharge a part of the gas. admitted into the piping, and the engine operates upon what is .termed the storage method, this being more economical than the normal workin Should the avionwith the engine now rise from the ground, the pressure of the air drawn into the engine will diminish. The filling of the cylinders is first corrected by i the handle 58 so as to gradually suppress the storage and to maintain a constant storage pressure and therefore a constant power, this condition prevailing until the pressure becomes reduced by 25 per cent of the normal pressure. If the avion continues to rise, one gradually closes the relief valve 43, thus reducing the air flow between the chambers as well as the successive connection of 95 the chambers with the exterior, and raising the pressure of the air in said chambers and also the filling pressure of the cylinders, with respect to the outside pressure, until the rise shall be equal to the difference between the outside pressure and 1 kilogram per square centimeter, or the constant filling pressure, this being obtained by a suitable position of the relief valve, the operation continuing until complete closing of said valve. At this moment the avion has attained the altitude for which the outside pressure is about kilogram per square centimeterdue to the partition arrangement in the crankcase and the discharge into the cylinders-.-less about 25 per cent of 1 kilogram, due to the storage, oran outside pressure of some 300 grams per square centimeter.

a The lever 44- of the relief valve, the cam shaft lever 58, and the lever of the correcting cocks 63 of the carburetters 47 and 48 maybe automatically controlled by an auxiliary device according to the pressure of ,the outer air, for example the device represented at each end of the engine. ,Said device com prises a cylinder 64 connected with the suction passages of the engine between 62 and 49, 50 and containing a piston 65 which is pressed by a spring 66, the rod of said iston being suitably connected with han les, 44,58 and handles 67 of cocks 63.

With the engine on the ground and inoperative, the piston 65 remains lifted by the spring and also by atmosphericpressure, a

I that the handles are in the positions shown in Figs. 1 and 2. But when the engine is running, the air discharged into the suction piping is compressed ata high pressure so as to drive'down the piston 65, and this pro duoed firstly the lengthwise motion of shaft providing for the operation upon storage, secondly the rotation of the relief valve 43 into the opening position, and thirdly the adjustment of the cooks 63 used for regulating the gasoline pressure. Upon opening the valve 43 the compression in the suction piping is reduced and the piston 65 assumes a position of equilibrium such that the communication between chambers 31, 32, and with the-air shall sufiice to produce the desired regulating.

When the engine is lifted in the flight, the air becomes gradually rarefied thereby reducing the pressure of the inlet into for casing 28 and consequently diminishing the pressure in the inlet piping of the cylinders. Piston 65 will be gradually lifted, thus moving the cam shaft 55 so as to reducethe extent of the storage, gradually closing the valve 43 so as to increase the compression ratio -in the crankcase chambers and also regulating the 'correcting cocks 63. By these means, when properly adjusted, the engine power can be automatically maintained at a practically constant value at-all altitudes up to a certain limit.

Inasmuch as the discharge of gas under pressure into the inlet piping requires an increase of the tension of the springs 67 pressing down the inlet ..valves, it may be advisable in some cases to provide balancing means for said valves, for example as shown in Fig. 6. In this event the stem of the valve 52 carries a piston 68 whose surface is somewhat smaller than that of the valve and movable in a cylinder 69 connected with the exterior, whereby the pressure of the fresh gas shall be caused to act in opposite directions upon the valve and the piston, and in this case the tension of the spring 67 can be muchreduced.

Claims:

1. In an internal combustion engine with multiple cylinders wherein the crankcase is divided into various chambers, each chamber communicating with two cylinders whose respective pistons move in concordance but whose inlets are opened in an alternate manner, communicating means for connecting each chamber of the crankcase with the atmosphere and with another chamber of the crankcase, cocks regulating the fuel feed to the engine, and means for common control of said communicating means and said regulating cocks.

2. In an internal combustion engine with multiple cylinders wherein the crankcase is divided into various chambers, each chamber communicating with two cylinders whose respective pistons move in concordance but whose inletsare opened in an alternate manner, communicating means for connecting each chamber of the crankcase with the atmosphere and with another chamber of the crankcase, a revoluble and slidable cam shaft provided with cams of variable outline for opening the engine inlet valves, and means for common control of said communicating means and said cam shaft.

3.111 an internal combustion engine with multiple cylinders in V disposition and wherein the crank case is divided into various chambers, each chamber communicating with two cylinders whereof the pistons act upon acommon crank and operate in concordance, but wherein the admission elements are alternately opened, communicating means for connecting each of the said chambers of the crank case with the atmosphere and with another chamber of the crank case, and controlling means which are movable in one direction by the pressure prevailing in the admission conduit of the engine and in the other direction by a reacting force, said means controlling the said communicating means substantially as described and for the purpose set forth.

4. In an internal combustion engine, the

combination of various pairs of cylinders,

pistons for the same, acrankcase divided by partitions into chambers whereof each communicates with one of the cylinder pairs,

a revoluble valve device disposed on one side of the crankcase and adapted to open and close the air inlet to said chambers in concordance with the strokes of the respective pistons, an inlet conduit, a revoluble valve device disposed at the top of the crankcase and adapted to open and close the communication between said chambers-and said inlet THEODORE LAFITTE. 

